American Power Conversion SYMSTRF-PD, SYMINIF-PD Modes of Operation, Load-Disconnect Mode

Modes of Operation

The Power Array functions in one of four modes of operation, depending on user commands, the status of the AC utility voltage, and the condition of the SymmetraTM itself. The four modes are Load-Disconnect, On-Line, On-Battery, and By- pass. The PowerView interface reports the operating mode.

Load-Disconnect Mode

In the load-disconnect mode, incoming AC utility power is present and the system is internally powered, but no output power is delivered to the load equipment. The SymmetraTM enters the load-disconnect mode at the initial power up, when the system enable switch is switched to the“on”position. When the system is operating on-line, and the “load off” command is entered in the PowerView interface, it returns to the load- disconnect mode. Figure I-3 illustrates the power flow when the system is operating in the load-disconnect mode.

Fig I-3Load-Disconnect Operating Mode

On-Line Operating Mode

The on-line operating mode is the “normal” operating mode. When the system is in the on-line operating mode, the Power Array receives power from the AC utility, and delivers condi- tioned power to the load equipment. The Power Array main- tains proper battery charge, regulates the output voltage and frequency, and protects the load from surges and electrical noise. SymmetraTM will operate in this mode if it has been commanded to turn the load on, the incoming utility voltage is present and functioning properly, and there are no prevent- ing abnormal conditions, such as an overload. See figure I-4 for a diagram of the power flow when the system is in the on- line operating mode.

Fig I-4On-Line Operating Mode

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